net.server_epoll: Refactor Direct TLS assumptions outwards
The assumption that connections are "Direct TLS" when a TLS context is
supplided should be broken. The goal is to make it easy to add a new API
that can be given a TLS context at creation even if it should do
STARTTLS.
With this commit, only the exposed server_select-compatible API assumes
Direct TLS when a TLS context is included.
== 1.0 ==
- Roster providers
- Statistics
- Clustering
- World domination